1. Field of Invention
This invention relates to hemical reaction processes. More particularly, this invention relates to highly efficient processes for preparing acrylic acid esters.
2. Prior Art
The preparation of carboxylic acid esters has been carried out employing a wide variety of chemical reaction processes. For example, carboxylic acid esters have been prepared by reacting corresponding carboxylic acids, acid anhydrides or acid chlorides with various hydroxyl containing materials.
One important category of esterification reactions involves the formation of acrylic or methacrylic acid esters of mono or polyhydric alcohols. U.S. Pat. Nos. 4 053,504 and 4,059,721 are typical of the patents relating to processes for forming acrylate esters. Both of these patents involve processes wherein essentially "cold" reactants are mixed together in a reactor and heated to reaction temperature. As the reaction proceeds, the water of reaction is removed and the temperature continues to rise until the reaction is completed.
In general, carboxylic acid-based esterification reactions are relatively slow, often requiring as long as 12 to 24 hours to complete.
Accordingly, it is an object of this invention to describe an esterification process which reduces the time necessary to carry esterification reactions to completion.
It is another object of this invention to reduce the costs of conducting esterification reactions by reducing the amount of time necessary to carry out the reaction.
Another object of this invention is to prepare esters of polyhydroxy materials such as the acrylate or methacrylate esters of pentaerythritol, trimethylolethane, or trimethylolpropane.
These and other objectives are obtained by carrying out the process of the instant invention.